pubsub

gistfile1.rb

require "delegate"

class PostsController < ApplicationController
  respond_to :html, :json

  module PubSub
    def add_observer(observer)
      (@observers ||= []) << observer
    end

    def publish(event, *args)
      @observers.each do |observer|
        observer.send(event, *args) if observer.respond_to? event
      end if @observers
    end
  end

  class PostMailer
    def post_created(post)
      Rails.logger.info "-- sending email"
    end
  end

  class HtmlResponder < SimpleDelegator
    def post_created(post)
      redirect_to post, notice: 'Post was successfully created.'
    end

    def post_create_failed(post)
      render action: "new" 
    end
  end
  

  class PostCreator
    include PubSub

    def initialize(post)
      @post = post
    end

    def create
      if @post.save
        publish(:post_created, @post)
      else
        publish(:post_create_failed, @post)
      end
    end
  end

  def create
    @post = Post.new(params[:post])
    post_creator = PostCreator.new(@post)
    post_creator.add_observer HtmlResponder.new(self)
    post_creator.add_observer PostMailer.new(params)
    post_creator.create
  end
end